NEW YORK (TheWrap.com) – The showrunner of “Hell on Wheels” has parted ways with the AMC western soon after the announcement that it would return for a third season.

Though AMC has high-profile clashes before with some of its showrunners, statements from AMC and showrunner John Shiban suggested that that was not the case this time. The show’s renewal depends on a new lead writer and producer being named to take over the direction of the series, but AMC expressed confidence that this would happen.

It also said Shiban had “made the personal decision that he will be unable to return as showrunner.”

“He has asked the production partners to seek a replacement showrunner,” AMC said in a statement. “Like all of our shows, network pick-ups are always conditioned on an approved showrunner. We are confident that eOne and Endemol will satisfy that obligation in the near future.”

Added Shiban, in a statement released through AMC: “I’m very proud of our work on ‘Hell on Wheels’ and was thrilled to hear the show would have a Season Three. I have since made the difficult decision that the time has come for me to leave. I care deeply about the series and will do whatever I can to aid in the transition to ensure the continued success of the show. I truly value all the time I have spent with this wonderful group of very talented people.”

Shiban is the second showrunner to depart an AMC show. “Walking Dead” executive producer Frank Darabont exited after its first season. “Mad Man” creator and showrunner Matthew Weiner also threatened to leave after difficult negotiations with the network last year